Date: Tue, 04 Jun 1996 22:11:36 -0700 From: "Michael L. VanLoon -- HeadCandy.com" <michaelv@HeadCandy.com> To: "Justin T. Gibbs" <gibbs@freefall.freebsd.org> Cc: Sean Eric Fagan <sef@kithrup.com>, smp@freebsd.org Subject: Re: Unix/NT synchronization model (was: SMP progress?) Message-ID: <199606050511.WAA25213@MindBender.HeadCandy.com> In-Reply-To: Your message of Tue, 04 Jun 96 16:53:02 -0700. <199606042353.QAA23687@freefall.freebsd.org>
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>>But maybe I'm not stating myself clearly. :-) What I'm really after is
>>recommendations on where I should look if I want to see how another
>>SMP Unix implements synchronization controls. I just want to find out
>>how other people have implemented it. All I know is Windows NT (SMP,
>>not in general, of course), and I want to see a contrasting
>>implementation.
>Aren't you really asking about thread and process syncronization? This is
>an issue regardless of whether the system is SMP.
Well, yes, they're not strictly related. But, I have yet to see a
non-SMP Unix where they cared about such things.
So, in reality (in my mind, anyway -- whether that's reality is
subject for a different debate... ;-), a decent SMP Unix precedes good
process/thread synchronization facilities, and an SMP Unix with lousy
process/thread synchronization facilities would probably suck at being
SMP. (Does that make sense?)
Anyway, the way I see it you need *some* kind of synchronization to
get the kernel running MP. What would be the most beneficial
synchronization primatives to get the kernel running? I don't know --
I think it's pretty obvious my kernel MP experience is about this big:
-><-. I can think abstractly about what it would take to make such a
thing -- I'm just struggling a little on the actual implementation.
Terry posted a very interesting little tome today on this subject.
Now, if I can get him to boil it down to pictures and words I can
understand, I'll be in really good shape. :-)
Anyway, from what he said, it sounds like I have the right concepts in
place in my head. I just need to work on filling them out. I'll go
read some books and some code instead of bugging this list with a
whole bunch more questions, though. :-)
>I've also only dealt with the NT implementations of critical sections and
>mutexes, and unlike the rest of the win32 API, it seems they did a fairly
>good job of it (although there are some additional scheduling controls I
>wish were provided).
Yes, in general I think the NT kernel has a lot of cool things going
for it. It's all the gunky Windows-based API layers above it that
make NT so bloated. I wouldn't mind seeing userland process/thread
synchronization facilities like those in NT.
Which is why I want to see how it's done in a modern Unix. Maybe
there's a "better" way. Or, at least a more "standard" way. It would
be kinda dumb to put together a bunch of sync stuff that looks like
NT, nice as it might be, when everything else written for an MP or
threaded Unix works totally different. I don't want to be locked into
an NT paradigm.
-----------------------------------------------------------------------------
Michael L. VanLoon michaelv@HeadCandy.com
--< Free your mind and your machine -- NetBSD free un*x >--
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